Re psk125 Yes lots of variables. Unfortunately the time for experimentation has passed. She is out of the water for the winter now. I have however tried most of the things you suggest. Mizen up, mizen down, stay sail up, stay sail down, sails in, sails out, sails tight, sails loose. I get a pretty good impression of what is happening across the ground with the track on the chart plotter. The angle of tack stubbornly refuses to improve. The Endurance 35 was never designed as a performance boat and it may well be that this is the way it is.
The real test would be if out there there was another E35 owner with whom I could compare notes.
Thanks for your comments they are much appreciated. At the moment I am planning to change the current yankee/stay sail arrangement for a genoa. I’m hoping this will improve drive and ease sail handling. Fingers crossed.